1. Field of the Invention
This invention relates to fixed or rigid thermocouple mountings having provisions to avoid metallic deposition on the mounting during case formation on ferrous articles.
2. Description of the Prior Art
It has heretofore been proposed, as described in American Society for Metals, Metals Handbook, Vol. 2, commencing at p. 677, to carburize the surface of a ferrous work piece or ion nitride the surface of a work piece to provide a case which may be hardened as the case is formed or which may subsequently be hardened.
Examples of ion nitriding by ionization in a chamber of a nitrogen containing gas are shown in the U.S. Patents to Egan, U.S. Pat. No. 1,837,256, Berghaus et al., U.S. Pat. No. 2,837,654, Keller, U.S. Pat. No. 3,761,370, Jones et al., U.S. Pat. Nos. 3,437,784 and 3,650,930, and Tanaka et al., U.S. Pat. No. 4,109,157.
Materials that are sputtered from the work travel in straight lines, tend to build up on work supports and other exposed elements in the furnace and may cause electrical shorting. The tendency to shorting is greatly reduced in this structure by the use of shields which comprise insulating discs and spacers supported on the mounting.